Process for production of high quality petroleum products



Patented Sept. 11, 1951 UNITED r 2,567,175 I PROCESS FORrnonUc'riofifdiit ififl" mi; I

QUALITY PETROLEUM PR'BDUGTS' Ewin maternaib Aefi kkailis' fi i Q N. J.,assi'gii'arstb Standardgil Development Qompany, a corporationoiiljelaware T 7 Application January 12, 1949, serial Nm70;424

, 1 The invention c improved process for the mutation or high tainingcritical amounts of an aldehyde, pa-r= ticularly formaldehyde.

In the production pfhhighquality petroleum products as for example. inthe production ,oi petroleum products boiling in the ,motor ifuelboiling range itis knownto ,usehvarious proce; dures. These proceduresgeneraljare directed toward removing constituents from the motor fuelswhich cause harmful results to the engine when consumed. The proceduresalso are directed toward retaining? in the gasmmes thede smmeeonstitiie'rits and also aired-ted toward securing maximum yields ofthe, desired prod; ucts. In the chemical treatment oipetroleu'riifractions boiling the r'notorIuel boiling" range, the use ofconcentrated s'ulfuric acid is well known. This acid 'r'e'i'nov'i'ssulfur compounds wen as various unsaturated di l'efi'ns and relatedcompounds which cause deleterious results in the en ine when the' flielis burned. Whi'lth' use of sulfuric acid pro ces a satisfactoryprodnotcertain roblems eirist withrespect to use. w en a cracked sto k itreated with sub fume acid 'for the removal or mercaptans and othersulfur ,edmiaoufid's as well as olfinic con:

stituents, iicessivepoi iheri'z'ation of tom the desirable afid un iesle ii'y'drec r dn ccns'titw ents occurs, resul mg inlan incr asp? in phe'ss of gasoline to higher boiling polymers. Further more: n a wa verare? e i t pr -furic acid is used which is necessafy'under tier itClaims. (01.;1'9

I tain conditicnse fixd xle fti Sat the hydrocarbon ,.frac on .92tyndesircblen qnr stituents it is necessary. tQ ubseguently ;swe etenthe,=,gasoline, usually by means of the so-called doctorqtreatiw A new.,processwhaseniiw eheened scbv igl,IQ!

the "production, oihi heq a ity. petrole m. M951:

ucts, particularlygasolinesu Inmaccordance with the, present inventionipetroleumw fractiqn parz. ticulariycracked petroleum fraction arereated. with dilute acids in, the presence of, a controlled amount ofanaldeh-yde as forexampleformalde;

hyde. The invention visespee a ly c nqe ened with the use o'fvvsulfuriciacid hayingaconcentrar tion. not in,excessnofabout l9,0%pandpreierably having a .concentrationinrthe range/ from, algout Aparticular desired wac on tra .1. v for use in, accordance with theprocess oj the present invention ,is a, sulfuric acid haying a on ntations the range, .i qmi'about :67? e amount or ald h de employ dis. intl an e ofiaboutjto 5% and is preferablyin the range from about, 11.5mm3 0%,y The preferred aldehyde the crawlin azi eed ,,o. w ch for thepmnqse v of illustration; assumed tope a gas oil boiling in the .ranesfr'drfiap ut 400, to. 700i nfir d ceq mimic-ra kin l0- byhme neocf eine tis m. euefiere qq t at he}??? 1 m .e Q E RE'iNSQLa ee eeedsi tu e osimilar crackingied stock Ora king zone I while iiyafocazrtaii fractionmotor fuel boiling range is withdrawn from zone 20 by means of line 4and introduced into storage zone 5. Also, for the purpose ofillustration it is assumed that a hydrocarbon fraction boiling in thekerosene boiling range is removed from zone 20 by means of line 6 andintroduced into storage zone I. Hydrocarbon fractions boiling in thediesel fuel boiling range are removed from zone 20 by means of line 8and introduced into storage zone 9. Higher boiling hydrocarbons areWithdrawn from zone 20 by means of line I l and further distilled orhandled in any manner desired.

In accordance with conventional practice, the respective streams fromzones 5, I and 9 are individuallytreatedflasfollows. Forj purpose'of i1-lustration the treatment of the hydrocarbon fraction boiling in themotor fuel boiling range is described.

The hydrocarbon fraction is withdrawn from storage zone by means of linel2 and combined with concentrated sulfuric acid having the concentrationin excess of about 95 weight per cent which is introduced into thesystem by means of line [3. Satisfactory mixing is secured by passingthe streams through orifice mixing devices. and then introducing thestream into settling zone 30. Acid sludge is withdrawn from zone 30 bymeans of line l5 while the treated oil is withdrawn by means of line l6.-Water is introduced into the system by means of line H and the oil andwater pass through orificemixing devices 18. The mixture is introducedinto zone 40 and a water layer withdrawn by means of line IS. The oillayers withdrawn by means of line 2| are combined with dilute causticwhich is introduced by means of line 22. Mixing is secured by orificemixing devices or equivalents 23. The stream is introduced into zone 50from which a spent caustic phase is withdrawn by means of line 24. Theoil phaseis withdrawn by means of line 25 and introduced intodistillation zone 60. Hydrocarbon constituents, as for 'examplepolymerized hydrocarbons boiling above the-motor fuel boiling range, arewithdrawn from zone 60 bymeansof line 26, while the hydrocarbonfractions boiling in the motor fuel boiling range are withdrawn fromzone 60 by means of line 21. This stream is then passed into treatingzone 10 wherein the same is treated'with a doctor solution in order toconvert objectionable sulfur compounds into relatively harmlessdisulphides. The final product is withdrawn fromzone 10 by means of line28.- l l I In accordance with the present invention the cracked productis treated with a dilute acid, preferably a dilute sulfuric acidcontaining a critical amount of an aldehyde, preferably a formaldehyde.In-accordance with a preferred adaptation of the invention, theformaldehyde is introduced into the oil stream by means of line 29 andthe oil and formaldehyde mixed in orifice mixer or equivalent 80. Theacid is then added as described by means of line I3. It is, however, tobe understood that the formaldehyde may be added to the acid and thedilute acid containing the formaldehyde then contacted with the oil.When operating in'accordan'ce with the present invention the overheadstream removed from zone 60 by means of line 21 comprises a finishedproduct and it is thuspossible to by-pass doctor treating zone 10. Thefinished product is removed from the system by means of line 3|.

The present invention may be more fully understood from the followingexamples illustrating various embodiments of th same.

EXAMPLE 1 A thermally cracked hydrocarbon fraction boiling in thegasoline boiling range (60 F. to about 400 F.) was treated at 70 F. with60% sulfuric acid containing 5% by weight of formaldehyde based ongasoline fed. The volume of acid used per volume of oil was 20%. Theacid layer was separated from the oil layer. The oil layer was waterwashed, caustic washed and then steam distilled. The results of thistreatment are as follows: I I

' TAB L E fi if ASTM Diolefin 1S Peroxide Total Gum, Break- Oontent [100down N 0 Sulfur Untreated Frac- Per cent Per cent "on 2. 95 196 185 1. 10. 137 Treated Fraction; l. 46 5 1, i40+ 0. 2 0. 046

1 ASTM designation D 525-46. 2 Milliequivalents of peroxide 0: perliter.

It is readily apparent that the quality of the treated cracked stock isvery much improved.

EXAMPLE 2 A steam cracked hydrocarbon fraction boiling in the range fromabout 185-400 F. was treatedsimilarly as described-in Example 1. Theresults ofv these tests areas follows:

TABLE II 40 Copper ASTM D1olefin Peroxide Dish Break- Content Gum downNo.

Untreated; 17. 5 2 230 o. 2 Treated 3.3 2 1,340 0.2

It is evident from Examples 1 and 2 that the treatment of the crackeddistillates produced a reduction of diolefin concentration, sulfur,copper dish gum and an improvement in oxidation fins, and boiled between150?, F; and 430 F; In

operations G to K the concentration of the 'sulfuric acid'strength wasvaried while in operations A to F the concentration of the acid strengthwas also varied in the presence of 5% formaldehyde based on theweight ofthe hydrocarbon fraction. In all cases 20% of the acid solution wasemployed based upon the volume of the oil being treated. The treatedfractions were finished in a manner similar to that described inExamples 1 and 2. The results of these operations are TABLE III Refiningcracked distillates with. formgjdejwdei efliect of catalyst (Hedge) [Inpresence of ionngl de h e1 ofitglgst ASTM D'h v 2 4 0 remxide Total Dilefin Run Strength Break- Gum er ;Br.No.

Per cent down Mg/100cc. sulfur 1, content by Wt. =1

@er, cent 13a cent 95 629 12 o.9 1 f0.217 47.5 1 2.75 s 32 1 1 0.2 a0.078 31.2 0.57 645 1 0.3 0.135 1 41.3 0.42 595 15 1 0.1 0.153- 33.70.52 550 10 1 0. a 0. 180 40. o o. 50 305 101 1 0. a 0.107 41.8

1 General operating conditions utilized: 5% (EH on gasoline. 6 hours at0 Steam distillation of tre (813113I oximately 94% formaldehyde, 5%methanol and 1% water).

I g. mercaptan sulfur/100 cc. 3 Gram equivalents active oxygen/1000liters.

4 Centigrams oi bromine/gram. Control-water washed, neutral TABLERefining cracked d by weight on gasoline. ated gasoline. 'In'operat 2Qvol. per cent ofecid ion ions pararormaldehyde employed ized with N22011, and steam redistilled.

, fiieetei Ma e Ji gth.

I [In-absence of formaldehydel ofiavtglgst AsTt/i 0 D 11 J V 1S .C .2 Proxide Total Diolefin Run Stren th Break: Gum, Opper e B11. No. Pertint; 1155 11" Mama. e 5 1i"? i Per. cent Per cent G e0 275 5 0.4 0.18641.5 1.22 H. 50 205 371 6 0L 5 0. 216 44.3 1. 70. I- 40 105 485 10 0. 40. 233 46.4 1. 23. I- 3 .0. 60,0 12 Q. 234 44.4 2. 1; 20 85 704 16 0.646.9.

Genei-al operating conditions uti1izedr20 vol. per cent of acid solutionon gasoline. 6; hqursat Steam distillation of treated gasoline. i lM. g.n ercaptan sulfur/100 co. 3 Grain equivalents act've oxygen/1000 hters.

{.Centigra oi bromin [gr n From the data presented in Tables. l ll and/IV, it is apparent that the stability as measuredby the ASTM breakdowntest is improved. It is also apparent that the sulfur and gum: content.

[G eneral operati ng condi of formaldehyde. A very desirable acidconcentration is about 50-60%.

EXAMPLE 4 Additional operations were conducted varying the amount of H504 employed, the formaldehyde concentration and the time of contactemploying 60% sulfuric acid concentration. The results of. theseoperations are presented in Tables V, VI, The treated products werefinished as'desoribed in Examples 1, 2, and 3.

TABLE V Efiect of Catalyst Solution Volume s: 6Q%. E 2 SO4 catalyst. 5Wt. per cent 01120 on gasonie. 6 hour contact at, 25 0.]

Qrtam :ASTM 011131211 105 er- Peroxide Total e H8150 43x25 Gum; V No.Sulfur BLNO' A 20. s10. 32 1;- 0.2 .078 31.8 B 10. 755. 34 1 0.2 0.11234.1 0 5V 755 11; 0. 2 0. 101 as. 2

stem-7e TABLE Vi Eject of Formaldehyde concentration {General operatingconditions: 20 vol.

pe r cent 651% H2804 catalyst. 6 hour contact I Efiect of Contact Timeat 25 ci IGeneral conditions: 20 vol. per cent 607 1151153); catalyst.2.5 wt. per cent OHaO on gaso e.

ASTM Contact On Dish Copper Peroxide Total Run Time 32% Gum No. No.sum]:

Hours A 6 580 287 1 0. 1 0. 144 36. 4 B 3 680 16 1 0. 1 0. 119 38. 0 O 1550 4 1 0. 2 0. 122 I 35. 9

From Table V it is apparent that an increase in the volume of acidcatalyst solution produces a reduction in the sulfur content with verylittle effect on the breakdown, the gum, the copper number and theperoxide number. A preferred treat of 60% concentrated acid (H2804) isabout 10 to by volume of acid per volume of oil.

It is also apparent that an increase in the formaldehyde concentrationproduces an improvement in the breakdown characteristic, 2. reduction inthe copper number, a reduction in the sulfur content Without appreciablyefiecting the peroxide number or gumcontent.

Also when the contact time is increased, the gum and sulfur contents areincreased without changing the stability, copper number or peroxidenumber. It is therefore apparent that short contact times are desirable.

It is to be noted that the copper dish gum values as shown in Examples 3and 4 are relatively high due probably to the fact that the condensationproducts of formaldehyde with the undesirable gasoline constituentsdistill overhead with steam but do not evaporate in the copper dish gumdetermination. Superior results can be obtained particularly as regardsgum content of the finished gasoline by distilling the treated productdry instead of in the presence of steam as is shown by the examples.

EXAMPLE 5 Additional operations were conducted wherein the treatedcracked gasolines were removed from the acid layer, neutralized withcaustic soda, water washed and rerun in the absence of steam to an endpoint of 400 F. The effects of varying; formaldehyde concentration, acidsolution volume and temperature'were also determined. The results arelisted in Tables VIII, IX, X, and in.

TABLE VIII Control runs [One hour contact time at 25 0.]

ASTM Cu Copper Peroxide Total Per Cent Run Treat 3 83 No. No. SulfurPolymer! A 10 vol. per cent water"-.. I25 535 17 0. 4 0. 206 46.3 as B0.8 vol. per cent 96.6% 85 46 2 0. 1 0. 097 36. 3 8.0 H2804.

TABLE IX Effect of formaldehyde concentration:

, 1 t v [General conditions: 10 vol. per cent 60% H2804 catalystsolution. 1 hour contact at 25 0.]

l ASTM Cu Per Cent CHzO on 00 per Peroxide Total Per Cent Gasoline 32bFo. N o Sulfur Polymer 2,507,173 I 9 y y 1o.

nae-x I Eflect of acid solution volume [One hour contact at 25 0.]

ASTM Cu Copper Peroxlde Total Per Cent Run Treat #323 No. N o. Sulfur NPolymer l L v l. per cent 60% nisol 210 22 1 0 0. 5 0.187 39. 4 5. 7

a One. M 10 V10]. per cent 60% H2504 V 215 16 10 0. 3 0- 171 41. 1 5. 7

a one. N- 5 V01. per cent 60% H2804 375 62 1 0. 2 0. 140 38. 5 5. 1 +2%H2 0 locxglb 60% 1a,s0i2+2'7;, 345 s 2 0.1 0.125 40. s r 0 4.4 7

i i j.

1 Material boiling above 400 F. exgressed as per cent of volume oforiginal feed. 3 Molar equivalent to 2% formalde yde.

TABLE XI Effect of temperature .-[-Genera1 conditions: 5 vol. per cent60% HiSO cattsol. 1a wt. per cent 01120 (on gasoline). 1 hour contact anatc tint: Stir. rate 375 62 1 0.2 0.140 38.5 5.1 53 39c 34 2 0.1 0.12637.0 as

1 Material boiling above 400 F. expressed as per cent of volume oforiginal feed.

From Table VIII it is apparent that strong conproducts may be somewhatgreater. Formalin centrated sulfuric acid per seis not particularly (37%formaldehyde solution in water) can be desirable in that the. extent ofpolymer formation used in place of paraformaldehyde by adding conisrelatively high. Table IX indicates that a p centrated sulfuric acidthereto and adjusting the fcrred concentration o formaldehyde s in theacid solution concentration to the desired level range from about 1% to3%. with water,

The data also show in Table X that by increas- 5 ing the acid solutionvolume a reduction in gum 40 EXAMPLE 6 content, a reduction in peroxidenumber and a V reduction insulfur with no appreciable effect onAdditional p a s we e conducted wherein breakdown or copper number issecured. In a the time of contacting was Varied and the productcontinuous process the-use of 5 volume by acid redistilled. Theresultsofthese operations are is adequate. It is apparent (Table XI)that by 4 given in Table XII.

TABLE XII Refining cracked distillates with formaldehyde Efiect ofcontact time and rerunning [General conditions: 10 vol. per cent H2804catalyst. 2 wt. per cent 01120 (on gasoline) ASTM CuDish 00 per PeroxideTotal Per cent Gum N o. No. 7

Run Contact Time at 25 0. Break- I awn1 Sulfur Polymer 160 987 0ily 1 05 O. 179 37. 9

Control 25 535 oily-- 17 0 4 0. 6 46. 3 3. 8

1 Material boiling above 400 Rexpressed as per cent of volume oforiginal feed.

increasing the treating temperature, the sulfur, Although rerunning isnecessary to reduce the content is slightly reduced as well as the gumsulfur, the gum and the peroxide contents and to content. However, thestability, the copper numimprove the Stability, the mercap n content canbar and the peroxide number are not substanbe greatly reduce evenWithoutrerunnin F rtially changed. It is also apparent that as the.thermore, the acid lay an be r y 1 d ut t contact time is reduced, thesulfur and peroxide: 7o acid concentration should be held constant incontents increase. r order to secure uniform removal of the sulfur.

Gasolines treated with acetaldehyde (in molar equivalent quantities)possess properties substanv tially equal to those treated withformaldehyde The value of. aformaldehyde dilute acid treat althoughtheloss of gasoline to higher boiling 7 overv a conventionalconcentrated acid treat :is

ii further-illustrated by the following operational data: (Table XIII).

12 At, the end of 40 hours operation, the engine was dismantled andinspected. The deposits on TABLE XIII Comparison of formaldehyde andacid treating Motor 0. N. A ASTM T Run Treat Egreak- 333 83 55; 5323 Br.N 0. cc

Clear Pb o. N.

Per cent Per cent A- 18. 0 1. 55 0. 127 40 0. 4 69. 6 77. 7. 9

o--- {contr61'--.. 125 303 2.25 0. 230 51.1 2.2 70.3 16.3 5.5

lhourat 25 C----.;;--.;

From the above it is apparent that although the diene content issomewhat higher, the formaldehydetreated distillate possesses somewhatbetter stability (as measured by ASTM breakdown test) than theconcentrated acid treat. Thiswould indicate that the formaldehyde-diluteacid process is more selective. In addition, the same gasoline leadsusceptibility is obtained as can be obtained with the strong sulfuricacid process, but the sulfur content of the formaldehyde treateddistillate is not as low as that of the acid treated distillate. EXAMPLE8 Engine test data have indicated that the thermal and catalytic naphthafractions of the finished gasoline apparently contain the major valves,pistons, rings and combustion chamber were noted and the sludge in thelubricating oil measured. Allthese factors were taken into sults securedwhen running a high quality and satisfactory gasoline considered as areference fuel and rated as 100%. From the data it is evident that theuse of formaldehyde markedly improves the engine cleanlinesscharacteristics of the motor fuel. It is also evident that the diluteacid treat plus formaldehyde is superior to the concentrated acid treat,as a means of improving the engine cleanliness characteristics ofthermally and catalytically cracked fuels.

Crankcase Vent, C. F. H

varnish and sludge forming and stability reduce P se t invention is concrned w th he ing constituents. In order to demonstrate the production ofhigh quality petroleum oil prodsuperiority of the formaldehyde diluteacid treatucts. The invention is particularly directed to ment over theconcentrated sulfuric acid treatan improved processfor improving theengine ment as a means of improving the engine cleanlicleanlinesscharacteristics and oxidation stability ness characteristics ofgasolines, further operaof motor fuels especially thermally andcatalytitions were conducted on a blend containing 90% cally crackedgasolines. The invention is also untreated thermal naphtha and 10% heavycatadirectedtoward the production of gasolines havlytic naphtha. Thetreating results obtained on ing lower sulfur, gum, diene, and peroxideconthis blend are listed in Table XIV. I tents thereof. The processemployed broadly TABLE XIV Treating Losses 1 Engine Motor Test, RunTreat Total Octane per cent Sludge Polymer N0 rang/nee 1-.-. Blend rerunto 400 F. vapor tempnm'fnm 71.3 144 2..-. Blend treated with 66 30.E2804 (5 lbs.lbbl.),

water washed, neutralized and rerun to 400 F 2. 2 3. 2 5. 4 70.0 1183.-.- Blend treated with 1.5 Wt. per cent formaldehyde in the presenceof 10 Vol. per cent, H1504,

k2 hr. contact time finished as in run 2 3. 0 0. 4 3. 4 71. 3 113 4.-.-Sameasrun3butemploying3wt.percentformaldehyde 2. e 2. 2 4. s 70. a 100'1 As per cent by volume based on feed.

It will be noted that the loss of gasoline .to utilized a dilutetreating acid, preferably a sulhigher boiling polymer is lower onformaldehyde furic acid having a concentration not in excess dilute acidtreating than on concentrated sulof about 80% and preferably having aconcentrafuric acid treating in the absence of formaldeti in the ran efrom ab ut 55% t i cony mples of the treated gasolines were thenjunction with an aldehyde, preferably formalderun in a single cylinderLauson engine operated hyde. und r th f l w n nditi s: I The stocktreated may have a boiling ran e Engine Speed, M 1800 from about 50 F.to 700 F. although it is pre- Cmnkcase Temp" 145 ferred that the finalboiling point he not inex- Jacket Temp 95 7o cess of 450 F. It is alsopreferred that the I t k i T 1 0 bromine number of the feed be at least15 C. g. 011 Charge, Quarts. 0 5 Br./gm. The process can also be appliedto the Test Duration, Hours 40 treatment of other hydrocarbondistillates such Power Output, H. P 2.2 as heavy naphthas, kerosenes,heating oils, diesel .0- fuels and the like. It is to be understood that13 the entire fraction may be treated or that specific boiling rangefractions may be segregated and separately treated. Various cycle stockssecured from refining operations can likewise be treated in the mannerdescribed.

With respect to the method of treatment, it is preferred that theformaldehyde be added to the oil and mixed therewith followed by theaddition of acid. It is, however, to be understood that the formaldehydecan be added to the acid and this mixture used to contact the oil. Theacid layer segregated from the oil containing the formaldehyde may berecycled in order to contact fresh untreated oil. If sulfuric acid beused, it is preferred that the concentration be in the range from about30% to 80%, preferably in the range from 55% to 65%. The amount of acidsolution used is preferably from about 0.5 to volume per cent based uponthe gasoline. The aldehyde concentration used is in the range from 0.5to 5% preferably from 1 to 3% by weight based upon the gasoline. Theconcentration of the aldehyde employed will to some extent depend uponthe unsaturation of the stock being treated. The time of contact may beas high as 60 minutes, although it is preferred that it not exceed to 30minutes. The temperature of contacting also is preferably in the rangefrom about to 60 C. Other acids of sulfur and phosphorus may be used, asfor example H2804, H3PO4 and the various sulfonic acids.

In the present invention any suitable aldehyde may be employed as forexample, acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde andacrolein. The preferred treating agent comprises formaldehyde which maybe used as such, but is preferably utilized in a commercial operation asan aqueous solution. A particularly de sirable aqueous solutioncomprises formalin (37 formaldehyde in water). However, it is to beunderstood that with respect to the present invention, if an aqueouscarrier be employed the concentration of the added acid must be adjustedaccordingly, since the acid concentrations specified are defined withrespect to the total water present in the treating zone irrespective asto whether the water is introduced with the acid, or aldehyde or fromother sources.

Other substances such as paraformaldehyde, trioxane, hexamethylenetetramine, methylal or equivalent substances which yield formaldehydemay be utilized.

Having described the invention it is claimed:

1. Improved process for removing constituents from hydrocarbons boilingin the motor fuel boiling range which tend to cause engine uncleanlinesswhen burned in internal combustion engines which comprises contacting aliquid petroleum hydrocarbon boiling in the motor fuel boiling rangewith a dilute aqueous mineral acid of about -80% concentration andcontaining from about .5 to 5% of an aldehyde by weight based upon thehydrocarbon feed.

2. Process as defined by claim 1 wherein said petroleum hydrocarboncomprises a cracked petroleum hydrocarbon.

3. Process as defined by claim 1 wherein said dilute acid comprisessulfuric acid and said aldehyde comprises formaldehyde.

4. Process as defined by claim 1 wherein said acid comprises sulfuricacid having a concentration in the range from about to 5. Process asdefined by claim 1 wherein said petroleum hydrocarbon boils in the rangefrom about F. to 400 F.

6. Improved process for the production of a high quality gasoline, whichcomprises contacting a liquid cracked petroleum fraction boiling in themotor fuel boiling range with a dilute mineral acid of about 30-80%concentration and containing from about .5 to 5.0% of formaldehyde byweight based upon the hydrocarbon feed, separating the acid layer,contacting the treated hydrocarbon fraction with a caustic solution andthen redistilling the same.

7. Improved process for the production of high quality motor fuels fromcracked distillates which comprises adding to said cracked distillatesfrom about .5 to 5.0% of formaldehyde, mixing the formaldehyde and thedistillate, thereafter adding to the distillate and the aldehyde arelatively dilute sulfuric acid of about 30-80% concentration,separating the acid sludge therefrom, treating the distillate with waterand thenwith a dilute caustic, separating the treated distillate andrerunning the same to segregate a hydrocarbon fraction boiling in themotor fuel boiling range.

8. Process as defined by claim '7 wherein the acid separated from thedistillate is recycled.

9. Process for removing constituents from hy- ERVING ARUNDALE. LOUIS A.MIKESKA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,964,953 Lazar July 3, 19341,998,292 Smith Apr. 16, 1935 2,011,199 Pele Aug. 13, 1935 2,080,732Morrell May 18, 1937 2,216,027 Smtih Sept. 24, 1940 OTHER REFERENCES J.I. P. T., 10, 99-100 (1924).

1. IMPROVED PROCESS FOR REMOVING CONSTITUENTS FROM HYDROCARBONS BOILINGIN THE MOTOR FUEL BOILING RANGE WHICH TEND TO CAUSE ENGINE UNCLEANLINESSWHEN BURNED IN INTERNAL COMBUSTION ENGINES WHICH COMPRISES CONTACTING ALIQUID PETROLEUM HYDROCARBON BOILING IN THE MOTOR FUEL BOILING RANGEWITH A DILUTE AQUEOUS MINERAL ACID OF ABOUT 30-80% CONCENTRATION ANDCONTAINING FROM ABOUT .5 TO 5% OF AN ALDEHYDE BY WEIGHT BASED UPON THEHYDROCARBON FEED.